Particle size dependence of the laser microfabrication of gold nanoparticles dispersed in polymer resists

Abstract

A laser microfabrication technique for a polymer film based on the absorbance of Au nanoparticles for realizing a nano-microstructure was proposed. The polymer films were made of ethylcellulose wherein Au nanoparticles were dispersed. Since the absorption spectrum, which influences laser processing ability, depends on the size of the Au nanoparticles in the polymer, four sizes of Au nanoparticles were prepared using a liquid-phase reduction method and a newly developed size control technique. The polymer films with Au nanoparticles of different sizes were processed using a Nd:YVO4-SHG laser. The results confirmed that the laser processing ability was unrelated to the absorption coefficient of the polymer film but the increase of the processed depth can be explained by the decrease of full width at half maximum of the absorption peak, indicated by the sharpness of the peak.